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  • November 18, 2019, 02:28:30 PM

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Author Topic: Royal Rodent fuel tank  (Read 695 times)

Offline Dave Nyce

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Royal Rodent fuel tank
« on: October 29, 2019, 01:46:27 PM »
I'm building a Royal Rodent, from Harter's Hobby Products.  The plan calls for a "New Darwin R-4 Tank".  A photo of the tank, as shown on the plan, is attached. I have two questions:

1. Is this tank available anywhere? Or if not, where can I get this tank made?

2. I don't see on the plan where the fueling line(s) come out of the fuselage. If anyone is familiar with this plane, do I have to remove the top of the fuselage for fueling?

Thanks!
Dave Nyce   Apex, NC 
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Online Motorman

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Re: Royal Rodent fuel tank
« Reply #1 on: October 29, 2019, 02:04:34 PM »
I've never seen a Royal Rodent but I assume it's some kind of pan rat. The vent and the over flow come out of the fuselage at the split line. I could make that tank but I hesitate to do so without the pan in hand.


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Online bill bischoff

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Re: Royal Rodent fuel tank
« Reply #2 on: October 29, 2019, 02:36:55 PM »
I make and sell lots of tanks. I can make you one like the drawing for $20 plus shipping. PM me. I can put the fill and overflow wherever you want if you have a different idea than the drawing.

Bill Bischoff

Online bob whitney

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Re: Royal Rodent fuel tank
« Reply #3 on: October 29, 2019, 02:48:19 PM »
the royal rodent was an up right pan rat racer by Harters .it came out just after the Midwest Rat which was a two piece all wood take apart kit.Both from back in the 60's the tank. u show is better fitted to the Mid West Rat as it was more or less square in shape. the Rodent used the round Harters proto pan .it used a round tank shaped to fit the pan .when used for racing it had a 3/8 or 1/2 tube that came up through the fuse with a rubber quick fill in it . I am sure there are quite a few laying around from the old 40 rat days maybe some one will chime in with one.
rad racer

Offline Bob Heywood

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Re: Royal Rodent fuel tank
« Reply #4 on: October 29, 2019, 07:54:56 PM »
I built my Royal Rodent in 1961 and powered it with a Fox 8 - Bolt 35 Combat Special. The fuel tank I used was the Darwin R-4. The engine was set up for crankcase pressure so the rear overflow vent was capped off. As Walt said the pressure vent just cleared the pan and stuck outside the plane. That had to be done so the pit crew plane holder guy could pull off the pressure line while the pit crew motor guy could fill the tank through the fuel feed line. Fast Fills were still in the future. I don't recall exactly how I secured the tank but it didn't seem to be a big deal. The attached pic shows a production Darwin R-4 tank.

Darwin fuel tanks are long out of production.
"Clockwise Forever..."

Offline Paul Smith

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Re: Royal Rodent fuel tank
« Reply #5 on: October 29, 2019, 09:11:53 PM »
The standard tank for this was the Don's bongo drum, which fit perfectly in the Rodent & the Raider.  It came with the Don's duck call filler.

I've still got a flyable one from 1970.  Sorry, I don't have a pitcher inside.  I haven't had the top off since maybe 1983.

The tank is a tapered cylinder that fits the pan snuggly.  It's secured with Dow silicone bathtub sealer.

The round hole behind the engine is filler, the rectangular thing is shutoff reset.
Paul Smith

Offline Paul Smith

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Re: Royal Rodent fuel tank
« Reply #6 on: October 30, 2019, 09:21:27 AM »
I found one I still have.

They were made by Don Hoyer of Cincinnati or maybe Dayton.  There were the way to go until the early 1970's when rat 40's go so big they wouldn't fit the $2.95 Harters pans anymore.  The bigger more powerful 40's also demanded more fuel.


Paul Smith

Online Motorman

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Re: Royal Rodent fuel tank
« Reply #7 on: October 31, 2019, 07:33:28 PM »
Dave, Are you building this for Fox35 speed? I have to tell you a design that has a high wing and a low stab is prone to pitch oscillation which is why they went to Vee tails on upright speed ships. It might not happen if the fuselage is long enough but it's something to watch for.


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« Last Edit: November 03, 2019, 08:04:39 AM by Motorman »
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Offline Mike Hazel

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Re: Royal Rodent fuel tank
« Reply #8 on: November 03, 2019, 04:43:26 PM »
Dave,  I have some Don's rat race tanks available if you are interested.  The valves are long gone, but you can get them from Brodak.

1 -  Donís 2-1/2 oz Rat Race, no valve  -LN     $5.00 ea
2 -  Donís 4 oz Rat Race,  no valve  -LN      $5.00
1 -  Donís xtra long ď5 ozĒ Rat Race, no valve LN   $6.00

Online bob whitney

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Re: Royal Rodent fuel tank
« Reply #9 on: November 03, 2019, 05:30:49 PM »
guess I am too late .was at a stunt contest today and someone was selling a bunch of tanks and I found a Dons tank for $5 so bought it ,if u want it ,it is yours. if not no big thing
rad racer

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